O2 Sensor Heater Circuit Malfunction (Bank 1, Sensor 1)
Plain-English meaning
The engine control module (ECM) has detected a problem with the heater circuit of the oxygen sensor located before the catalytic converter on bank 1. This heater helps the sensor reach operating temperature quickly for accurate readings.
What to check first
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What not to replace yet
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Stop driving when
It is generally safe to continue driving with this code, but if you experience severe engine performance issues such as stalling or rough running, stop driving and seek professional assistance.
Related symptoms
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Owner steps
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Likely causes
Faulty oxygen sensor heater element (medium)
Blown fuse related to oxygen sensor heater circuit (medium)
Damaged wiring or connectors in the heater circuit (medium)
Corroded or loose electrical connections (medium)
Faulty ECM (rare) (medium)
Shop steps
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Follow-up questions
Has the check engine light been on continuously or intermittently?
Are there any noticeable changes in engine performance or fuel economy?
Has any recent work been done near the oxygen sensor or wiring?
Have you noticed any exhaust odors or unusual noises?